FIG. 6 shows a usual example of a multi-connected connector directly attached to a printed circuit board. The multi-connected connector 100 is disclosed in a below-described PTL 1 and includes a plurality of first connectors 110 and a second connector 120 to which the first connectors 110 are fitted and attached.
The second connector 120 is provided, as shown in the drawing, in a form that a plurality of connector fitting chambers 121 are arranged in a row in a transverse direction. Each of the connector fitting chambers 121 is a part to which the first connector 110 is fitted and attached.
Further, in the case of the multi-connected connector 100 shown in FIG. 6, the second connector 120 is provided with a simultaneous fitting detecting member 130. The simultaneous fitting detecting member 130 is a member that simultaneously pushes in rear ends of the plurality of first connectors 110 temporarily attached to the connector fitting chambers 121 respectively to their normal fitting completed positions. The simultaneous fitting detecting member 130 has one end side connected to the second connector 120 so as to freely rotate by a hinge 131 and is pressed respectively to the rear ends of the first connectors 110 by a rotating operation.
When all of the plurality of first connectors 110 are pushed in to the normal fitting completed positions by a pushing-in operation of the simultaneous fitting detecting member 130, an engaging hook 132 provided in the other end of the simultaneous fitting detecting member 130 is engaged with an engaging part provided in the second connector 120, so that the simultaneous fitting detecting member 130 is fixed to a rear end of the second connector.
Namely, in the multi-connected connector 100, when a part of the first connectors 110 are located in a half inserted state that the first connectors 110 do not reach the normal fitting completed positions, the engaging hook 132 of the simultaneous fitting detecting member 130 is not engaged with the engaging part of the second connector 120 side. Thus, it can be detected whether or not the first connectors are located in the half inserted state in accordance with that state.
In the case of the multi-connected connector 100 shown in FIG. 6, forms and dimensions of all the plurality of first connectors 110 attached to the second connector 120 are the same. However, the multi-connected connector may include such structures as shown in FIG. 7 and FIG. 8.
A multi-connected connector 100A shown in FIG. 7 and FIG. 8 includes a plurality of first connectors 110a, 110b, 110c and 110d and a second connector 120A to which the first connectors 110a, 110b, 110c and 110d are fitted and attached.
The second connector 120A is provided, as shown in the drawing, in a form that a plurality of connector fitting chambers 121a, 121b, 121c and 121d are arranged in a row in a transverse direction. The connector fitting chambers 121a, 121b, 121c and 121d are respectively parts to which the first connectors 110a, 110b, 110c and 110d are fitted and attached.
The plurality of first connectors 110a, 110b, 110c and 110d are different in their dimension of width due to the difference of the number of accommodated connecting terminals or the forms of terminals.
Further, in the first connector 110c, a length in a fitting direction is shorter than those of other first connectors 110a, 110b and 110d. 
Further, as shown in FIG. 9, in the connector fitting chambers 121a, 121b, 121c and 121d of the second connector 120A respectively, butting walls 122a, 122b, 122c and 122d are provided.
The butting walls 122a, 122b, 122c and 122d are positioning parts on which end surfaces of the first connectors 110a, 110b, 110c and 110d abut to determine fitting completed positions of the first connectors 110a, 110b, 110c and 110d. 
In the case of the usual multi-connected connector, the above-described butting walls 122a, 122b, 122c and 122d are arranged in a row in a transverse direction so as to align their positions as shown in FIG. 9.
Accordingly, when all the first connectors 110a, 110b, 110c and 110d are pushed in to normal fitting competed positions, as shown in FIG. 10, a rear end of the first connector 110c whose length in the fitting direction is smaller is more recessed by the difference L1 of fitting length than rear ends of other first connectors 110a, 110b and 110d 
On the other hand, when the first connector 110c whose length in the fitting direction is smaller is located in a half inserted state, and when other first connectors 110a, 110b and 110d are located in completely inserted states where the first connectors are inserted to the normal fitting completed positions, the recessed part of the first connector 110c whose length in the fitting direction is smaller is more reduced than that in a normal case, or as shown in FIG. 11, the rear end 110c is aligned with the positions of the rear ends of the other first connectors 110a, 110b and 110d. 